Linear material modification



June 10, 1969 5.1. JONES 3,448,574

LINEAR MATERIAL MODIFICATION Filed Aug. 5, 1968 I INVENTOR- E VAN I. J'w/es Arrow/61s June 10, 1969 Filed Aug. 5, 1968 E. l. JONES LINEAR MATERIAL MODIFICATION Sheet 3' 0:2

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Arum/ears United States Patent 3,448,574 LINEAR MATERIAL MODIFICATION Evan Islwyn Jones, 20 Sycamore Crescent, Macclesfield, Cheshire, England Filed Aug. 5, 1968, Ser. No. 750,112 Int. Cl. D02g 3/02; D01h 13/26 US. Cl. 57-157 20 Claims ABSTRACT OF THE DISCLOSURE The invention relates to a method of modifying a linear material, for instance to impart increased bulk and/or stretch, or simply to split the linear material into longitudinal strands. The term linear material is used herein to mean any material whose length is greatly in excess of its other dimensions and includes tapes, ribbons, films, monofilament and multifilament yarn, either singles or plied and not necessarily of uniform composition, and threads composed of staple fibre, either singles or plied, and of uniform composition or of blends.

It is well known that a yarn can be altered in character by stressing the yarn under suitable conditions. Falsetwisting undercontrolled temperature and tension in particular increases the bulk of textile yarns.

According to the present invention there is provided a method of modifying a linear material in which a leading portion of the travelling material is coiled a multiplicity of turns around a trailing portion of itself in such a manner that the material in both portions is travelling in substantially the same direction while the portions are intertwining. To make this possible it is necessary first to form the material into at least one loop; the leading end then enters the intertwining zone at the same point as the trailing portion and leaves this zone at another point, so that thereafter both portions of the material assist rather than hinder one anothers forward progress. Depending on the modification to be effected to the material it may be necessary to localize the intertwining zone, to a span substantially fixed in space; to control the number of intertwined turns, and therefore of turns per inch; to control the material input and output speeds; and to impose other conditions, appropriate to the material and to the end result required, which will achieve this modification. For instance, in the case of polyproplene ribbon, stress in the form of tension is all that is required to fibrillate the ribbon into strands, thus making it more suitable for certain end uses. Or again in the case of thermoplastic yarn it is advantageous to heat the yarn under controlled tension followed by cooling before the twist has been removed. This results in a considerable increase in the bulking propensity of the yarn when in fabric form.

Embodiments of the invention will now be described, by way of example only, with reference to the accompanying diagrammatic drawings, in which:

FIG. 1 is a diagram illustrating the principle of the invention;

FIG. 2 illustrates one apparatus for carrying out the invention;

FIG. 3 is a view similar to FIG. 1 showing a modification;

FIG. 4 illustrates an alternative apparatus for carrying out the invention; and

3,448,574 Patented June 10, 1969 FIG. 5a to 5d illustrate a mechanical means of coiling one end of yarn round another.

Referring to FIG. 1, a yarn from a bobbin 1 is formed into a loop 2 over suitable rollers and/or guides (not shown) and the leading portion is coiled a multiplicity of turns round the trailing portion at 3 before it proceeds forward for collection or further processing.

FIG. 2 illustrates a form of apparatus by means of which, using the process of this invention a thermoplastic, heat-settable yarn can be converted into a bulked yarn. The yarn enters at 4, at the bottom of FIG. 2, passes through tension discs 5, then through guides 6 and 9 and over pisitively driven rollers 10 and 11 to return through guides 6 and 9 between which it coils round itself a multiplicity of turns 8, having then formed one complete loop 7, so that both portions of the yarn in the spiral coil travel in the same direction. From the guide system 9 the yarn passes between a pair of positively driven nip rollers 14 and on to a windup package 16, which is positively driven by a roller '15. Two electric plate or block heaters 12 and 13 situated respectively below and above guides 6 are heated to a controlled temperature by means of a thermostatic servomechanism (not shown) so that the yarn is plasticized. Heater 12 can be used alone so that only the leading segment of yarn is plasticized, or heater 13 can be used alone. Heater 13 does not extend the full length of the spiral coil between guides '6 and 9, so as to allow yarn cooling to take place before the yarn emerges from this coiling zone, the cooling being either natural or forced.

It is preferable, although not essential, that modification of the trailing portion of the yarn is kept to a minimum. When heater 13 is used this condition is achieved by controlling the relative tensions of the two portions, with a higher enough tension in the trailing portion relative to that in the leading portion to cause the former to remain relatively straight, and form a core yarn round which the leading portion spirals. The trailing portion is then insulated, or partially insulated, from the heater by the leading portion. In any case a relatively low tension is preferable in the leading portion of yarn to avoid pulling out the crimp. This requirement is achieved in this apparatus by adjusting disc tension 5, to for instance 0.2 gm./denier or more, and adjusting the overfeed between roller system 10, 11 and nip roller system 14 to give a tension of 0.1 gm./denier. These tensions and speed re lationships depend, of course, on the yarn denier and chemical composition, on the heater temperature, on the length of heater and on the actual throughput rate.

It is also preferable that the relationship between heater length and throughput rate be such that a heating time of between 0.25 second and 2.5 seconds is maintained. It is also preferable that a cooling period of this order be maintained in the coiling zone for the crimp to become properly set before leaving this zone. A suitable temperature for nylon 6 yarn is -195 C., and for nylon 6, 6 or Terylene polyester yarns is 220240 C.

FIG. 3 differs from FIG. 1 only in that a total of four loops are shown instead of only one. Yarn from a supply bobbin 17 is formed into four loops before the leading portion and the trailing portion of yarn intertwine to form the spiral coil 19.

In FIG. 4, this multiple loop system is used for extending the heating length of the leading yarn portion while maintaining the trailing yarn portion relatively cold. In the apparatus shown, yarn 20, from a supply bobbin or from a previous processing stage is fed between positively driven nip rolls through a guide 22, into guide systems 23 and 24, round pulley 25 to form several wraps or loops round a system of positively driven rollers 26 and 27, and into guide systems 23, 24 to be taken up by a positively driven roller/separator roll system 29 before collection or proceeding to the next process. Rollers 26, 27 are enclosed in a heat box 28, having heating means (not shown) and a door for threading-up and general access purposes. The relative speeds of rolls 21, 26, 27 and 29 are such as to maintain the conditions of actual and relative tension in the two intertwined yarn portions, as measured just below guide system 23 and just before roller system 29, substantially as for the process illustrated in FIG. 2. In this process the provision of means for assembling a multiplicity of coils of yarn makes it possible to maintain 0.25 second to 2.5 seconds heating time in a small space while running the yarn at high throughput rates. The distance between guide systems 23 and 24, now entirely available for cooling the yarn still should preferably allow sufficient dwell time for the crimp to be properly set.

In the above illustrations no mention has been made of the coil direction, whether right-hand or left-hand, nor of the number of turns per inch in the coil. These are of course two important aspects of this crimping process.

In general only one direction of coiling is possible in one zone; moreover both strands involved coil around each other in this same direction once they are threaded up. There is no reason, however, for the yarn at a later time not to be coiled in the opposite direction on the same equipment. This is an advantage, because the yarn produced by this process is twist-lively due to the torque impressed on it and fabrics produced from it will in general exhibit spirality. This may be overcome very satisfactorily in a number of alternative ways. Either two such crimped yarns of opposite torque are plied together, or are fed alternatively into a fabric, or yarns of one torque direction are posttreated in order to suppress the torque without undue loss of bulk.

The number of coil turns per inch is determined by the denier of the yarn. In general the range of values preferred lies between that suitable for the false-twisting of the denier in question, using a twist spindle, and the twist suitable for a yarn of twice this denier. For example, using 40 denier 13 filament nylon 6, 6 yarn the number of coil turns per inch should preferably be between 70 and 110. This arises because there are two coils of yarn of 40 denier in the coil. The number of coil turns per inch is obtained by inserting this number according to the zone length, in the coiling zone, and is in this sense independent of the yarn throughput rate.

The required number of coil turns can be inserted in the yarn in many ways. Three methods will be described. In one method the yarn can be a composite thread composed of, for instance, one white and one coloured yarn, fed into the apparatus either from one package or from two. In this case, the composite yarn can be seen to be twisted consistently in one direction over the free length prior to the coil position. This direction of twist is the same as the direction of coiling, and this twist can with advantage be set into the yarn in addition to coil-setting.

In another method the yarn can be fed continuously either from packages or from a previous process such as drawing, and can thus form part of an integrated extrusion, drawing and texturing process. It can be integrated also with later processing stages, such as stuffer-box crimping, down-twisting, plying, knitting, oiling and/ or cutting. In such cases yarns from several coil-setting or auto-twist zones or units can be combined as they enter the next processing stage.

Another method employs a mechanical means of inserting the required number of coil turns in the yarn, this being in the form of a false-twist spindle 30 as shown in FIG. 5. The spindle is only rotated during this initial coil formation. For this purpose the spindle is inserted so that the pulley or twist-peg is upstream from the entry guides 31 so that these two systemsthe entry guides and the twist peg define the coiling zone. The yarn is threaded through the first guide system 31 then through the axial hole in the spindle so that it passes through the gap underneath the twist peg. It is then looped round via exit guide system 32 and rollers 33, 34 (see FIG. 5a) and threaded once more through the first guide system 31 and through the axial hole in the spindle, this time so that it passes through the gap above the twist peg, and is led through guide system 32 to takeup rollers and from these to the windup package (see FIG. 5b). The spindle is then rotated clockwise 600 revolutions, this direction being as viewed from the left of the spindle, to insert S or right twist in the portions of the yarn between the twist peg and the first guide system, and Z or left twist in the segments above the twist peg (see FIG. 50). It is possible to process yarn using this system in three distinct ways. The two opposite twist coils of yarn may be allowed to remain, and the turns per inch relationship between them suitably adjusted by controlling the distances from the first guide system 31 to the twist peg and from the twist peg to the second guide system 32 to give, with appropriate heating and cooling conditions in both coils suitable posttreatment of the yarn emerging from the first coiling zone. Alternatively the twist peg can be rotated, in this instance 1200 turns periodically, with yarn running through, first anticlockwise, then clockwise and anticlockwise alternately, either with or without heating in the second coiling zone, to produce a dual'torque yarn. Or, again, the yarn emerging for the second time from the twist peg can be cut at this point, after coiling and stopping the twist peg, and the yarn led away to the takeup rollers and to the collection package, after only the one-stage crimping process (see FIG. 5d).

Various modifications may be made without departing from the invention. For example, although in the above description a twist pig is used, the process can be etfected using other means of coil separation such as a. ceramic plate or two pegs, one upstream of the other, so that the two coils are separated a convenient distance from each other. Moreover, while the embodiments described have used fixed guide systems and pegs, the process can also be operated using movable guide systems and/or pegs, or with certain members of these being movable, and, if necessary, responsive to and compensating for changes in yarn tensions, or forming an element or elements of a tension control system or systems. Other independent tension control systems may also be used.

What is claimed is:

1. A method of modifying a linear material in which a leading portion of the travelling material is coiled a multiplicity of turns around a trailing portion of itself in such a manner that the material in both portions is travelling in substantially the same direction while the portions are intertwining.

2. A method according to claim 1, in which the material is heated in the zone in which it is intertwined.

3. A method according to claim 2, in which the leading portion of the material is heated prior to the zone in which it is coiled around the trailing portion.

4. A method according to claim 2, in which heating is effected for between 0.25 and 2.5 seconds.

5. A method according to claim 3, in which heating is effected for between 0.25 and 2.5 seconds.

6. A method according to claim 2, in which the material is allowed to cool in a cooling zone after heating.

7. A method according to claim 3, in which the material is allowed to cool in a cooling zone after heating.

8. A method according to claim 6, in which cooling is effected for between 0.25 and 2.5 seconds.

9. A method according to claim 7, in which cooling is effected for between 0.25 and 2.5 seconds.

10. A method according to claim 1, in which diiferential tensions are applied to the leading and trailing portions of the material so that the trailing portion remains relatively straight and so forms a core around which the leading portion spirals.

11. A method according to claim 2, in which difierential tensions are applied to the leading and trailing portions of the material so that the trailing portion re- 5 mains relatively straight and so forms a core around which the leading portion spirals.

12. A method according to claim 3, in which differential tensions are applied to the leading and trailing portions of the material so that the trailing portion remains relatively straight and so forms a core around which the leading portion spirals.

13. A method according to claim 1, in which the leading portion of the material is formed into a plurality of loops before it is coiled round the trailing portion.

14. A method according to claim 2, in which the leading portion of the material is formed into a plurality of loops beforeit is coiled round the trailing portion.

15. A method according to claim 3, in which the leading portion of the material is formed into a plurality of loops before it is coiled round the trailing portion.

16. A method according to claim 13, in which said loops are located in a heating chamber.

17. A method according to claim 14, in which said loops are located in a heating chamber.

18. A method according to claim 15, in which said loops are located in a heating chamber.

19. A method according to claim 1, in which the material is coiled upon itself first in one direction and then in the other.

20. A method according to claim 1, in which the number of coils per inch lies between that suitable for the false-twisting of the denier of the material in question and the twist suitable for a material of twice this denier.

References Cited UNITED STATES PATENTS 2,881,504 4/1959 Billion.

2,963,848 12/ 1960 Finlayson et a1 57--34 3,010,271 11/1961 Batsch 57-157 XR 3,035,396 5/1962 Biggers 57157 XR 3,050,819 8/1962 Allrnan et a1. 57-34- X'R 3,148,520 9/1964 Biggers 2872 XR 3,178,795 4/1965 Warthen 5734 X'R 3,192,697 7/1965 Carruthers 5734 3,261,116 7/1966 Kunzle et al 5734 3,411,282 11/1968 Hampel 57-34 DONALD E. WATKINS, Primary Examiner.

US. Cl. XJR. 

